[nozebleed1]

Both my cts 3.6 DI did it, just curious. one was louder than the other it seems. and this one ticks then goes away then louder then goes away

 

[CSIMME01]

I think what you are hearing is the high pressure fuel system. Because it's a direct injection engine the fuel pressure in that part of the system is 1500-4500 PSI.

 

[Padgett]

Just a niggle but more like 500-600 at idle. Tank pump on top, DI pump on bottom. 4 MPA is about 580 psi

 

[CSIMME01]

Just a niggle but more like 500-600 at idle. Tank pump on top, DI pump on bottom. 4 MPA is about 580 psi
View attachment 592960

You got me there.
The numbers I quoted were for a generic DI engine
I didn't look up specific GM 3.6 pressures.
Normal range of the 3.6 is 2 to 15bar

 

[Padgett]

GM ranges are usually chosen to avoid warranty clams.

 

[CSIMME01]

GM ranges are usually chosen to avoid warranty clams.

Which is a good thing.

 

[Lifespeed]

Which is a good thing.

The argument could be made that, in the context of the timing chain error range, it is allowing wear to near-catastrophic levels. The CEL light definitely does not indicate timing chain wear when it is bad enough to degrade driveability, performance and fuel economy. I think it was clear this was just a warranty claim dodge and not made with the consumer's best interests in mind.